Turbine wheel and supercharger

Abstract

The turbine impeller provided by the invention is arranged in a turbine shell of the supercharger. The turbine wheel includes a hub and a plurality of blades. The hub is connected to a rotating shaft of the supercharger. The plurality of blades are provided on the hub at intervals in the circumferential direction with respect to the rotating shaft. The plurality of blades include at least one first blade and at least one second blade. The shape of the first blade and the shape of the second blade are different from each other.

Description

Technical Field

[0001] The invention relates to a turbine impeller and a supercharger. Background Art

[0002] Superchargers are commonly found in internal combustion engines such as those found in large ships and automobiles. Superchargers utilize the flow of exhaust gas generated within the internal combustion engine to rotate a turbine wheel, which in turn rotates a compressor wheel coaxially mounted with the turbine wheel. The compressor wheel delivers high-pressure air to the combustion chamber, thereby increasing the power output of the internal combustion engine.

[0003] For example, the turbine wheel of the supercharger disclosed in Patent Document 1 is rotated by the flow of exhaust gas passing through a vortex flow path formed in the turbine housing. The exhaust gas passing through the turbine wheel is discharged to the outside through a gas outlet formed in the turbine housing.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6796214 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] The rotation of the turbine impeller sometimes produces unusual sounds. For example, these unusual sounds can occur when the blades of the turbine impeller interfere with the vortex generated in the tongue portion formed on the inner wall of the turbine housing, or when the blade tips of a subsequent turbine impeller interfere with the vortex generated by the blade tips of a preceding turbine impeller. According to the inventors' findings, when a specific relationship exists between the number of blades and the turbine impeller's rotational frequency (or a frequency obtained by multiplying this rotational frequency by an integer greater than or equal to 2), there is a significant tendency for these unusual sounds to occur.

[0009] An object of the present invention is to provide a turbine impeller and a supercharger capable of suppressing the generation of abnormal noise.

[0010] Means for solving technical problems

[0011] A turbine impeller according to at least one embodiment of the present invention is a turbine impeller provided in a turbine housing of a supercharger, and includes:

[0012] a hub connected to the rotating shaft of the supercharger; and

[0013] A plurality of blades are provided on the hub at intervals in a circumferential direction based on the rotation axis.

[0014] The plurality of blades include at least one first blade and at least one second blade having a shape different from that of the first blade.

[0015] A supercharger according to at least one embodiment of the present invention includes:

[0016] The turbine impeller described in the above embodiment; and

[0017] a turbine housing, accommodating the turbine impeller,

[0018] The turbine housing comprises:

[0019] a vortex portion having a vortex flow passage formed therein, the vortex flow passage being located radially outward of the turbine impeller and configured to allow exhaust gas to flow in the circumferential direction; and

[0020] The tongue portion is formed on the inner circumference side of the vortex flow channel.

[0021] Effects of the Invention

[0022] According to the present invention, it is possible to provide a turbine impeller and a supercharger capable of suppressing the generation of abnormal noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic cross-sectional view showing a supercharger according to one embodiment.

[0024] Figure 2 This is a schematic cross-sectional view of a turbine casing according to one embodiment.

[0025] Figure 3 This is a schematic meridian cross-sectional view of a turbine impeller according to one embodiment.

[0026] Figure 4 This is a schematic diagram showing a blade according to one embodiment.

[0027] Figure 5 This is a schematic diagram showing the shape of the leading edge of the first blade according to one embodiment.

[0028] Figure 6 This is a schematic diagram of a turbine impeller according to another embodiment. DETAILED DESCRIPTION

[0029] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. The dimensions, materials, shapes, and relative arrangements of the components described in the embodiments or shown in the accompanying drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0030] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" that indicate relative or absolute configurations not only indicate that configuration in a strict sense, but also indicate a state with a tolerance, or a state of relative displacement at an angle or distance to the extent that the same function can be achieved.

[0031] For example, expressions such as “same,” “equal,” and “homogeneous” that indicate that things are equal not only indicate a state of equality in a strict sense but also indicate a state in which there is a tolerance or a degree of difference that allows the same function to be achieved.

[0032] For example, expressions indicating shapes such as a quadrilateral or a cylinder not only indicate shapes such as a quadrilateral or a cylinder in a strict geometric sense, but also indicate shapes including concave and convex portions or chamfered portions as long as the same effect can be obtained.

[0033] On the other hand, using words such as “have”, “include” or “has” to describe a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

[0034] In addition, the same symbols are attached to the same structures, and the description thereof may be omitted.

[0035] <Overall Structure of Turbocharger 1>

[0036] Figure 1 This is a schematic cross-sectional view of a supercharger 1 according to one embodiment of the present invention. The supercharger 1 in this example is mounted on a vehicle such as an automobile. In the following description, the radial and circumferential directions relative to the rotating shaft 2 of the supercharger 1 are sometimes referred to simply as the radial and circumferential directions, respectively. Furthermore, the axial direction of the rotating shaft 2 is sometimes referred to simply as the axial direction.

[0037] The supercharger 1 includes a rotating shaft 2, a compressor impeller 4 connected to one end of the rotating shaft 2, a turbine impeller 3 connected to the other end of the rotating shaft 2, a compressor housing 6 accommodating the compressor impeller 4, and a turbine housing 5 accommodating the turbine impeller 3. The compressor housing 6 includes an intake portion 10 having an intake passage 10A formed therein, and a scroll portion 8 having a scroll passage 8A formed therein.

[0038] Figure 2 This is a schematic cross-sectional view of a turbine housing 5 according to one embodiment of the present invention. The turbine housing 5 includes a vortex portion 7 having a vortex flow passage 7A formed therein and a tongue portion 51 formed on the inner circumference of the vortex flow passage 7A. The tongue portion 51 separates the vortex flow passage 7A from the flow passage 9 formed further in the direction of exhaust gas flow than the vortex flow passage 7A. The tongue portion 51 extends obliquely with respect to the axial direction (see FIG. 1 ). Figure 3 ).

[0039] <Turbine impeller 3>

[0040] Figure 3 : is a schematic diagram of a turbine impeller 3 according to one embodiment of the present invention. Figure 3 The turbine impeller 3 illustrated in FIG. 5 is a radial flow turbine, but the present invention is not limited thereto, and a diagonal flow turbine or the like may be employed. Figure 3 The arrow R in represents the rotation direction of the turbine impeller 3 .

[0041] The turbine impeller 3 includes a hub 31 having a Figure 1 ) axis S inclined hub surface 32; and a plurality of blades 33, provided on the hub surface 32. The hub 31 is connected to the rotating shaft 2. The plurality of blades 33 are spaced apart in the rotation direction of the hub 31, and each blade 33 includes a leading edge 35, a trailing edge 36 and a blade tip 37. In addition, as Figure 3 As shown, only long blades may be provided on the hub surface 32 of the turbine impeller 3, or long blades and short blades (not shown) may be provided. However, in the embodiment in which long blades and short blades are mixed, all of the plurality of blades 33 correspond to long blades.

[0042] refer to Figure 4 , defining the two ends of the leading edge 35 , namely the tip side end 39 and the hub side end 38 . Figure 4 : This is a schematic meridian cross-sectional view of a blade 33 according to one embodiment of the present invention. The tip-side end 39 is a portion of the leading edge 35 that is connected to the blade tip 37. The hub-side end 38 is a portion of the leading edge 35 that intersects with a virtual line L9 extending from the hub surface 32 toward the leading edge 35. Here, the virtual line L9 is a main line (i.e., a line that includes the hub 31) when viewed along the rotation direction of the turbine impeller 3. Figure 4 In addition, Figure 4 The virtual lines L1 to L8 illustrated in the figure are virtual curves that equally divide the area between the blade tip 37 and the hub surface 32 in the span direction. Furthermore, in the following description, the portion of the trailing edge 36 that connects to the blade tip 37 may be referred to as a trailing edge tip-side end 41, and the end of the trailing edge 36 opposite to the trailing edge tip-side end 41 may be referred to as a trailing edge hub-side end 42.

[0043] Return to Figure 3 When the position in the rotational direction is considered the rotational phase, the leading edge 35 of this embodiment exhibits a twisted shape such that the rotational phase changes as the position in the axial direction changes. More specifically, the leading edge 35 is formed so that the rotational phase at the hub-side end 38 differs from the rotational phase at the tip-side end 39. In the following description, the difference in rotational phase between the two may be referred to as the leading edge tilt angle.

[0044] The leading edge inclination angle is related to the time required for the blade 33 to pass through the tongue 51. This required time is the time from when the hub-side end 38 of the leading edge 35 passes through the tongue 51 to when the tip-side end 39 passes through the tongue 51.

[0045] As the supercharger 1 is driven, a vortex is generated inside the turbine housing 5. For example, at least one of a vortex generated near the tongue 51, a vortex generated near the leading edge 35 of the blade 33, or a vortex generated near the trailing edge 36 of the blade 33 is generated inside the turbine housing 5 (the vortex generated near the tongue 51 is generated by the Figure 2 (Indicated by arrow A in the figure). If blades 33 periodically strike the vortex, the vortex gradually intensifies, eventually generating an abnormal sound. The inventors of this application have come up with the following concept: by irregularizing the pattern of strikes between blades 33 and the vortex during each rotation of the turbine impeller 3, the intensification of the vortex can be suppressed, thereby suppressing the generation of abnormal sound. The following describes, as the first and second embodiments, structures that embody this concept.

[0046] <Specific Structure of Turbine Impeller 3 (First Embodiment)>

[0047] refer to Figure 3 、 Figure 5 The specific structure of the turbine impeller 3 according to the first embodiment will be described. The plurality of blades 33 includes at least one first blade 11 and at least one second blade 12. The first blade 11 and the second blade 12 have different shapes. Various structures can be employed to achieve different shapes between the first blade 11 and the second blade 12. For example, the shape of the leading edge 35 can be different between the first blade 11 and the second blade 12, or the shape of the trailing edge 36 can be different between the first blade 11 and the second blade 12, or a combination of these structures can be employed. When the shape of the leading edge 35 is different, the shape of the portion of the leading edge 35 on the blade tip 37 side can also be different, or the shape of the portion of the leading edge 35 on the hub side 38 can also be different. Alternatively, the leading edge inclination angle, described below, can also be different. When the shape of the trailing edge 36 is different, the shape of the portion of the trailing edge 36 on the blade tip side 41 can also be different, or the shape of the trailing edge 36 on the hub side 42 can also be different, or a combination of these structures can be employed.

[0048] According to the above configuration, since the first and second blades 11, 12, having different shapes, are included in the plurality of blades 33, even when vortexes are generated within the turbine housing 5, the pattern of collision between the plurality of blades 33 and the vortexes during each rotation of the turbine impeller 3 can be irregular, thereby suppressing the intensification of the vortexes. Consequently, the turbine impeller 3 can suppress the generation of unusual sounds. Furthermore, if the leading edges 35 of the first and second blades 11, 12 have different shapes, the time required for the leading edges 35 to pass through the vortexes generated near the tongue portion 51 of the turbine housing 5 becomes irregular. This prevents the leading edges 35 from periodically interfering with the vortexes, thereby suppressing the generation of unusual sounds. Furthermore, if the trailing edges 36 of the first and second blades 11, 12 have different shapes, the time required for the trailing edges 36 to pass through the vortexes generated near the trailing edges 36 of the blades 33 becomes irregular. This prevents the trailing edges 36 of the blades 33 from periodically interfering with the vortexes, thereby suppressing the generation of unusual sounds.

[0049] refer to Figure 5 , a specific structure in which the shape of the leading edge 35 is made different between the first blade 11 and the second blade 12 is illustrated. Figure 5 This is a schematic diagram showing the shape of the leading edge 35 of each of the first blade 11 and the second blade 12. In the area of ​​the diagram where the dotted line and the solid line overlap, the solid line is given priority. The horizontal axis of the diagram is the axial distance starting from the trailing edge tip side end 41, and corresponds to Figure 4 The vertical axis represents the position in the circumferential direction, that is, the rotation phase (θ), and the positive direction of θ is the rotation direction of the turbine impeller 3 ( Figure 3 The thick solid line shown on the graph represents the Figure 4 The relationship between the rotation phase of the first blade 11 and the axial distance is indicated by the blade tip 37, and the normal solid line indicates the relationship between the rotation phase of the first blade 11 and the axial distance is indicated by L9. Furthermore, the thick dotted line indicates the relationship between the rotation phase of the second blade 12 and the axial distance is indicated by the blade tip 37, and the normal dotted line indicates the relationship between the rotation phase of the second blade 12 and the axial distance is indicated by L9. As can be seen from the graph, in the range of Za<Z1, the blade tip 37 and the virtual line L9 have approximately the same rotation phase. In other words, in the range of Za<Z1, the first blade 11 and the second blade 12 have almost no twist. On the other hand, in the range of Za≥Z1, the blade tip 37 and the virtual line L9 have different rotation phases from each other, which indicates that the leading edge 35 has a twisted shape.

[0050] Figure 5The dimensions α1 and α2 shown represent the leading edge inclination angles of the first blade 11 and the second blade 12, respectively. As shown in the two figures, the leading edge inclination angles are different between the first blade 11 and the second blade 12. The leading edge 35 of the blade 33 is likely to collide with the vortex generated near the tongue portion 51 of the turbine casing 5. In this regard, according to the above-mentioned structure, since the first blade 11 and the second blade 12 have different leading edge inclination angles, the time required for the leading edge 35 of each blade 33 to pass through the vortex can be made irregular. As a result, the leading edge 35 of the blade 33 can be prevented from periodically interfering with the vortex, thereby suppressing the generation of abnormal sounds.

[0051] In some embodiments, any two adjacent blades 33 among the plurality of blades 33 may have different shapes. For example, a configuration may be employed in which the plurality of blades 33 is composed solely of a plurality of first blades 11 and a plurality of second blades 12, with the first blades 11 and the second blades 12 being arranged alternately in the circumferential direction. With this configuration, the manner in which the blades 33 impact the vortex flow varies between two adjacent first blades 11 and second blades 12, thereby suppressing the generation of abnormal sound.

[0052] In some embodiments, the multiple blades 33 may have different shapes. For example, the leading edge inclination angles of all blades 33 may be different. This configuration further changes the way the blades 33 collide with the vortex during each rotation of the turbine wheel 3, thereby suppressing the generation of abnormal sounds.

[0053] In addition, although the example in which the shape of the leading edge 35 is different between the first blade 11 and the second blade 12 is described as a specific example of the first embodiment, the present invention is not limited to this. For example, a structure in which the shape of the trailing edge 36 is different between the first blade 11 and the second blade 12 can also be adopted. In the turbine casing 5, a vortex is sometimes generated near the trailing edge 36 of the blade 33. If each trailing edge 36 periodically hits the vortex, the vortex is enhanced, thereby generating abnormal sound. In this regard, by making the shape of the trailing edge 36 different between the first blade 11 and the second blade 12, the way in which the blade 33 hits the vortex can be made irregular, thereby suppressing the generation of abnormal sound.

[0054] <Specific Structure of Turbine Impeller 3 (Second Embodiment)>

[0055] Figure 6 This is another schematic diagram showing the specific structure of the turbine impeller 3. Figure 6 , a plurality of blades 33 constituting the turbine impeller 3 are schematically illustrated. The plurality of blades 33 include a plurality of first blades 11, and a blade gap Bs is formed between two first blades 11 arranged continuously in the circumferential direction. Figure 6In the example, the number of first blades 11 is three, and the number of inter-blade gaps Bs is three. At least one third blade 13 is disposed in each inter-blade gap Bs among the plurality of blades 33. The third blade 13 may have any shape different from that of the first blade 11. For example, it may have the same shape as the second blade 12 described above, or a shape different from that of the second blade 12.

[0056] In this embodiment, the number of the third blades 13 arranged in the three blade gaps Bs is different. Figure 6 For example, two third blades 13 are arranged in the first blade gap Bs, three in the second blade gap Bs, and four in the third blade gap Bs. This configuration makes it possible to make the periodicity at which the multiple blades 33 collide with the vortex during each rotation of the turbine impeller 3 uneven, thereby suppressing the growth of the vortex. This also reduces the generation of unusual noise.

[0057] exist Figure 6 The plurality of blades 33 illustrated in FIG are arranged so that the blade pitches have two or more types. Figure 6 In the embodiment, two third blades 13 are arranged adjacent to each first blade 11 on both sides, and the blade spacing (θ1) between the third blade 13 and the first blade 11 on one side is different from the blade spacing (θ2) between the third blade 13 and the first blade 11 on the other side. This relationship is established for each first blade 11. In addition, as an example, the blade spacing is the blade tip side end 39 (reference Figure 3 ) spacing.

[0058] With this configuration, the periodicity at which the multiple blades 33 collide with the eddy current during each rotation of the turbine impeller 3 can be made uneven, thereby suppressing the growth of the eddy current. This also reduces the generation of unusual noise. Furthermore, the blade pitches can vary across the multiple blades 33; even in this case, the aforementioned advantages can be achieved.

[0059] In some embodiments, the distance between any two adjacent blades 33 in the plurality of blades 33 is greater than 2° by dividing 360° by the number of the plurality of blades 33. Figure 6 In the example, both θ1 and θ2 are at least 2° greater than the aforementioned angles. This configuration makes the periodicity of the impact of the multiple blades 33 with the vortex uneven during each rotation of the turbine impeller 3, thereby suppressing the growth of the vortex. This also reduces the generation of unusual noise.

[0060] In some cases, the distance between the tip-side ends 39 of any two adjacent blades 33 among the plurality of blades 33 is within 3 degrees. With this configuration, the exhaust gas flow supplied from the swirl flow passage 8A can be sufficiently received, and thus the flow force of the exhaust gas can be efficiently converted into the rotational force of the turbine impeller 3, thereby suppressing loss and performance degradation of the supercharger 1.

[0061] Summary

[0062] For example, the contents described in some of the above-mentioned embodiments can be understood as follows.

[0063] 1) The turbine impeller 3 according to at least one embodiment of the present invention is provided in the turbine housing 5 of the supercharger 1 and includes:

[0064] A hub 31 connected to the rotating shaft 2 of the supercharger; and

[0065] A plurality of blades 33 are provided on the hub at intervals in the circumferential direction based on the rotation axis.

[0066] The plurality of blades include at least one first blade 11 and at least one second blade 12 having a shape different from that of the first blade.

[0067] According to the configuration 1) above, since the first and second blades, each having a different shape, are included in the plurality of blades, even if a vortex is generated within the turbine housing, the pattern of collision between the plurality of blades and the vortex is irregularized during each rotation of the turbine impeller, thereby suppressing the intensification of the vortex. Consequently, the turbine impeller can suppress the generation of unusual noise.

[0068] 2) In some embodiments, according to the turbine impeller described in 1) above,

[0069] Each of the plurality of blades comprises a leading edge 35,

[0070] The shape of the leading edge of the first blade and the shape of the leading edge of the second blade are different from each other.

[0071] The leading edge of the blade is more likely to collide with the vortex generated by the tongue portion formed on the turbine housing. Regarding this, the configuration in (2) above, because the leading edge shapes of the first and second blades differ, can make the time required for the leading edge of each blade to pass through the vortex irregular. This prevents the leading edge of the blade from periodically interfering with the vortex, thereby suppressing the generation of unusual noise.

[0072] 3) In some embodiments, the turbine impeller according to 1) or 2) above, wherein:

[0073] When the circumferential position is taken as the rotation phase, and the difference between the rotation phase on the hub side end 38 of the leading edge and the rotation phase on the tip side end 39 of the leading edge is defined as the leading edge inclination angle, the leading edge inclination angle on the first blade and the leading edge inclination angle on the second blade are different from each other.

[0074] The leading edge of the blade is prone to colliding with the vortex generated by the tongue portion formed on the turbine housing. Regarding this, the configuration described in 3) above, where the leading edges of the first and second blades are angled relative to each other, can make the time required for the leading edge of each blade to pass through the vortex irregular. This prevents the leading edge of the blade from periodically interfering with the vortex, thereby suppressing the generation of unusual noise.

[0075] 4) In some embodiments, the turbine impeller according to any one of 1) to 3) above, wherein:

[0076] Each of the plurality of blades comprises a trailing edge 36,

[0077] The shape of the trailing edge of the first blade and the shape of the trailing edge of the second blade are different from each other.

[0078] According to the configuration in 4), the time required for the trailing edge to pass through the vortex generated near the trailing edge of the blade can be irregularized. This prevents the trailing edge of the blade from periodically interfering with the vortex, thereby suppressing the generation of abnormal sound.

[0079] 5) In some embodiments, the turbine impeller according to any one of 1) to 4) above, wherein:

[0080] Any two adjacent blades among the plurality of blades have different shapes from each other.

[0081] According to the configuration of 5) above, the collision pattern between the blades and the vortex flow changes between two adjacent blades, thereby suppressing the generation of abnormal noise.

[0082] 6) In some embodiments, according to the turbine impeller described in 5) above,

[0083] The plurality of blades each have a shape different from one another.

[0084] According to the configuration of 6) above, since the collision pattern between the blades and the vortex flow is further changed during each rotation of the turbine wheel, the generation of abnormal noise can be suppressed.

[0085] 7) In some embodiments, the turbine impeller according to any one of 1) to 6) above, wherein:

[0086] The plurality of blades include a plurality of first blades,

[0087] At least one other blade (the third blade 13 ) is disposed in a blade gap (Bs) formed between two first blades arranged continuously in the circumferential direction among the plurality of first blades.

[0088] The number of the other blades arranged in each of the blade gaps having the same number as that of the plurality of first blades is different among the plurality of blade gaps.

[0089] According to the structure of 7), the period of collision between the plurality of blades and the vortex flow during one rotation of the turbine wheel can be made more uneven, thereby suppressing the strengthening of the vortex flow and thereby suppressing the generation of abnormal noise.

[0090] 8) In some embodiments, the turbine impeller according to any one of 1) to 7) above, wherein:

[0091] The plurality of blades are arranged so as to have two or more types of blade pitches.

[0092] According to the configuration of 8), the period of collision between the plurality of blades and the vortex flow during one rotation of the turbine wheel can be made uneven, thereby suppressing the strengthening of the vortex flow and thereby suppressing the generation of abnormal noise.

[0093] 9) In some embodiments, according to the turbine impeller described in 8) above,

[0094] The blade pitch between any two adjacent blades among the plurality of blades is greater than an angle obtained by dividing 360° by the number of the plurality of blades by 2° or more.

[0095] According to the configuration of 9), the period of collision between the plurality of blades and the vortex flow during one rotation of the turbine wheel can be made more uneven, thereby suppressing the strengthening of the vortex flow and thereby suppressing the generation of abnormal noise.

[0096] 10) In some embodiments, the turbine impeller according to any one of 1) to 9) above, wherein:

[0097] The distance between the tip ends of any two adjacent blades among the plurality of blades is within 3°.

[0098] According to the configuration of 10), since the exhaust gas flow supplied from the vortex flow path can be fully received, the flow force of the exhaust gas can be efficiently converted into the rotational force of the turbine impeller, thereby suppressing loss and performance degradation of the turbocharger.

[0099] 11) A supercharger 1 according to at least one embodiment of the present invention includes:

[0100] The turbine impeller 3 according to any one of 1) to 10) above; and

[0101] The turbine housing 5 accommodates the turbine impeller.

[0102] The turbine housing comprises:

[0103] a vortex portion 7 having a vortex flow passage 7A formed therein, the vortex flow passage 7A being located radially outward of the turbine impeller and configured to allow exhaust gas to flow in the circumferential direction; and

[0104] The tongue portion 51 is formed on the inner peripheral side of the vortex flow channel.

[0105] According to the configuration of 11), even when a vortex flow is generated near the tongue portion, the generation of abnormal sound can be suppressed for the same reason as in 1).

[0106] Explanation of symbols

[0107] 1-supercharger, 2-rotating shaft, 3-turbine impeller, 4-compressor impeller, 5-turbine housing, 6-compressor housing, 7, 8-vortex part, 7A, 8A-vortex flow channel, 9-flow channel, 10-intake part, 10A-intake channel, 11-1st blade, 12-2nd blade, 13-3rd blade, 31-hub, 32-hub surface, 33-blade, 35-leading edge, 36-trailing edge, 37-blade tip, 38-hub side end, 39-blade tip side end, 41-trailing edge blade tip side end, 51-tongue, A-arrow, Bs-blade gap, S-axis line, α1, α2-size.

Claims

1. A turbine impeller disposed in a turbine housing of a supercharger, the turbine impeller comprising: a hub connected to the rotating shaft of the supercharger; and A plurality of blades are provided on the hub at intervals in a circumferential direction based on the rotation axis. The plurality of blades include at least one first blade and at least one second blade having a shape different from that of the first blade.

2. The turbine impeller according to claim 1, wherein: Each of the plurality of blades comprises a leading edge, The shape of the leading edge of the first blade and the shape of the leading edge of the second blade are different from each other.

3. The turbine impeller according to claim 2, wherein: When the circumferential position is taken as the rotation phase, and the difference between the rotation phase on the hub side end of the leading edge and the rotation phase on the tip side end of the leading edge is defined as the leading edge inclination angle, the leading edge inclination angle on the first blade and the leading edge inclination angle on the second blade are different from each other.

4. The turbine impeller according to claim 1, wherein: Each of the plurality of blades comprises a trailing edge, The shape of the trailing edge of the first blade and the shape of the trailing edge of the second blade are different from each other.

5. The turbine impeller according to any one of claims 1 to 4, wherein: Any two adjacent blades among the plurality of blades have different shapes from each other.

6. The turbine impeller according to claim 5, wherein: The plurality of blades each have a shape different from one another.

7. The turbine impeller according to any one of claims 1 to 3, wherein: The plurality of blades include a plurality of first blades, At least one other blade is disposed in a blade gap formed between two of the plurality of first blades that are arranged continuously in the circumferential direction. The number of the other blades arranged in each of the blade gaps having the same number as that of the plurality of first blades is different among the plurality of blade gaps.

8. The turbine impeller according to any one of claims 1 to 3, wherein: The plurality of blades are arranged so as to have two or more types of blade pitches.

9. The turbine impeller according to claim 8, wherein: The blade pitch between any two adjacent blades among the plurality of blades is greater than an angle obtained by dividing 360° by the number of the plurality of blades by 2° or more.

10. The turbine impeller according to any one of claims 1 to 3, wherein: The distance between the tip ends of any two adjacent blades among the plurality of blades is within 3°.

11. A supercharger comprising: The turbine impeller according to any one of claims 1 to 3; and a turbine housing, accommodating the turbine impeller, The turbine housing comprises: a vortex portion having a vortex flow passage formed therein, the vortex flow passage being located radially outward of the turbine impeller and configured to allow exhaust gas to flow in the circumferential direction; and The tongue portion is formed on the inner circumference side of the vortex flow channel.

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